How to consume null payloads with spring-pulsar from Apache Pulsar topic?

Question

Consider the code for consuming messages from Apache Pulsar that is set up with spring-pulsar:

    @PulsarListener(
        subscriptionName = "hello-pulsar-sub-2",
        topics = "#{dataAssetService.getCompactedTopicsArray()}",
        properties = {"readCompacted=true"}
)
public void consumeEntireTopic(
        @Payload(required = false) String jsonString,
        @Header(PulsarHeaders.TOPIC_NAME) String topic,
        @Header(PulsarHeaders.KEY) String key,
        @Header(PulsarHeaders.PUBLISH_TIME) String ts
        ) throws IOException {
// code to handle message here
}

I need an information in listener on when is a given key deleted, i.e. a null payload (a.k.a. tombstone) is sent for that key.

With the code above, an assertion is thrown deep in spring code (org.springframework.messaging.support.MessageBuilder), when null payload arrives.

So the question is: how to configure @PulsarListener to receive messages with null payloads?

Answer 1

This is not currently supported, but will be supported via https://github.com/spring-projects/spring-pulsar/issues/506.